The present inventions relates to probes. More specifically, the present invention relates to high frequency electronic probes which are particularly well suited for nondestructive probing of devices having a high density I/O interface or connector.
In the testing of large systems during the initial bring up and including debugging of system hardware, special modifications are typically made to the product. A metal stiffener used to support the large system boards is machined so that an open access is provided to e.g., pins of a Multi Chip Module (MCM) as well as providing access to other points of interest. There are presently two methods used to measure system operations; destructive and nondestructive measurement techniques. These are accomplished either by direct soldering of probe connectors to the system board or by the use of an insulated template and probe arrangement. The first method, direct soldering, provides good high frequency measurements but has many limitations and disadvantages. These limitations and disadvantages include, for example, the requirement that the board must be removed from the test fixture each time a connection is to be soldered on, the number of connections present at any time is limited and the connections are susceptible to mechanical failure (e.g., such as being broken off). The second method, utilizing the probe template, offers a full range of interconnections, by means of holes drilled through a template made of an insulating material, at all signal locations as well as selected ground or voltage reference locations of the MCM. This arrangement is limited to measurements in the 500 MHZ bandwidth region. Thus, while this template arrangement is adequate for error injection and some mid-frequency a.c. measurements, it is not suitable for analysis of high frequency switching noise and circuit operation verification.
With the ever increasing of operational speeds of computer systems including mainframes, it becomes more and more difficult to provide accurate measurement of high frequency operational parameters such as switching noise, signal integrity, jitter measurements, measurements of differential signals, or of differential measurements of voltage to ground disturbances.